Photographic developer



Patented Nov. 10, 1936 UNITED STATES rno'rocnsrmc DEVELOPER Wilhelm Schneider, Dessau, and Gustav Wilmanns, Wolfen Kreis Bitterfeld, Germany, asslgnors to Agfa Ansco Corporation, Binghamton, N. Y., a corporation 01 New York No Drawing. Application May 11, 1935, Serial No. 20,984. In Germany May 19, 1934 7 Claims. (01. 95-88) Our present invention relates to a photographic developer.

One of its objects is a photographic developer. Another object is a photographic developer which is particularly adapted for fine grain development. Further objects will be seen from the detailed specification following hereafter.

A fine-grain development of a layer of silver halide emulsion has hitherto been produced, either by using para-phenylenediamine as the developing agents, either alone or mixed with other developing agents, or by protracting the time of development with use of usual agents, for example metol, in smaller quantity and with only a small proportion of alkali, and thus influencing the size 01' the grain. The first-named procedure is not satisfactory owing to the deleterious action of para-phenylenediamine on the skin. In the second method the developer is only partially consumed, since already after a short use the small proportion of alkali has been consumed.

This invention relates to a process of fine-grain development in which the developing agent used is a halogen substitution product of a 2-alkylaminophenol. The compounds are obtainable, for instance, by splitting a chloro-substituted 2-methylbenzoxazole dimethylsulfate in the presence of caustic soda and saponiflcation of the resulting acetyl product with hydrochloric acid. With a normal content of alkali and sulfite these agents develop slowly and with fine grain without the disadvantages of the older agents referred to above.

The developers have the further advantage that they do not produce fog. The position of the halogen atom in the molecule or the'introduction of two halogen atoms into the molecule afiords a means 01' rendering the developer more or less gradual in its action. As specific compounds suitable for the invention may be named: 4 -chloro-2-methylaminophenol, 5-chloro-2-methylaminophenol, 4: 5-dichloro -2-methylaminophe nol and 5: 6-dichlor'o-2-methylaminophenol.

The following examples-oi developers illustrate the invention:

Example 1 200 cc. of water 2 grams of 4-chloro-2-methylaminophenol 5 grams of sodium suliite (anhydrous) 10 grams of potassium carbonate 0.2 gram of potassium bromide.

The time of development at 18 C. is 10-15" minutes.

Example 2 200 cc. of water 1 gram of- 5-chloro-2methylaminophenol 5 grams of sodium sulflte (anhydrous) 10 grams of potassium carbonate 0.2 gram of potassium bromide.

The time ofdevelopment at 18 C. is 15 to 30 minutes.

Example 3 200 cc. of water 1 gram. of 4: 6-dichloro-2-methylaminophenol 5 grams of sodium sulfite (anhydrous) 10 grams of potassium carbonate 0.2 gram of potassium bromide.

halogenated 2-methylamino-phenol and an alkali.

4. A photographic developer including a dihalogenated Z-methylamino-phenol and an alkali.

5. A photographic developer comprising 200 cc. of water 2 grams of 4-chloro-2-methylaminophenol 5 grams of sodium sulfite (anhydrous) 10 grams of potassium carbonate 2.0 gram of potassium brodie.

'6. A photographic developer comprising 200 cc. of water 1 gram of 5-chloro-2 methylaminophenol 5 grams of sodium sulfite (anhydrous) 10 grams of potassium carbonate 0.2 gram of potassium bromide.

' 7. A'photographlc developer comprising WILHELM SCHNEIDER. GUSTAV WILMANNS. 

